[bsclifton]

I think what you're describing are the "Tip" buttons which can be added on a few supported sites (which can be disabled). They aren't selling anything- it's a feature which people can use if they like.

The server implementation for sync is mostly compatible with Chromium and can be used without Brave. Someone could clone https://github.com/brave/go-sync and stand up their own server. It would require some patches on top of Chromium (similar to what is done in Brave) to implement the authentication - but once that is done, all of the Chromium tools like chrome://sync-internals work just fine